On the Applicability of Coherent Flame Models to Simulations of Developing Turbulent Flames

Paper in proceeding, 2006

Coherent Flame Models of premixed turbulent combustion are applied to a developing, statistically planar, one-dimensional flame, which propagates in a statistically stationary, spatially uniform and isotropic turbulence not affected by the heat release in the flame. Theoretical analysis and numerical simulations show that the models yield a faster growth of normalized mean flame brush thickness than normalized burning velocity. At high Reynolds numbers, this trend appears to be basically wrong, because the development of the thickness and burning velocity is controlled by the large- and small-scale eddies, respectively, which are characterized by long and short time scales, respectively. Therefore, the Coherent Flame Models and, in particular, the closure of the consumption term in the flame surface density balance equation need further consideration to be applicable to developing flames.